Since photosensitive polyimides themselves possess pattern processability, process simplification is possible when compared with the pattern processing of an ordinary non-photosensitive polyimide using a resist, etc. Hence, they are currently is widely put to practical use as semiconductor protective films and insulating films, etc.
In the semiconductor industry, for the purposes of stabilizing the film-forming process, photosensitive polyimides having good stability with lapse of time are in demand.
Of the photosensitive polyimides employed in connection with semiconductors, those which include a poly(amic acid) structure undergo a lowering of viscosity due to hydrolysis of the polymer, etc, and so cannot be said to be sufficiently stable over time.
Surprisingly, we have found that a composition, with both good viscosity stability at room temperature with lapse of time and good photosensitive performance; is attainable, by controlling the poly(amic acid) degree of imidization and the number of photocrosslinking groups.
The problem addressed by this invention lies in providing an actinic radiation sensitive polymer composition with both good viscosity stability at room temperature with lapse of time and good photosensitive performance.